Transcript Chapter 1
Chapter 4 States of Consciousness Chapter 4 Overview What is consciousness? Circadian rhythms Sleep Dreams Meditation and hypnosis Psychoactive drugs What is Consciousness? Consciousness is everything of which we are aware at any given time-our thoughts, feelings, sensations and external environment How have psychologists’ views about consciousness changed since the early days of psychology? Early psychologists saw consciousness as psychological in nature Today’s psychologists use brain-imaging techniques to identify brain activity associated with different states of consciousness They view consciousness as a neurobiological phenomenon, rather than an exclusively psychological one What is the connection between altered states of consciousness and culture? Altered state of consciousness – A change in awareness produced by sleep, meditation, hypnosis, or drugs In some cultures, individuals deliberately induce altered states as part of tribal ceremonies or religious rituals Circadian Rhythms More than 100 bodily functions and behaviors follow circadian rhythms fluctuating regularly throughout each day In what ways do circadian rhythms affect physiological and psychological functions? Circadian rhythm – Regular fluctuation from high to low points of certain bodily functions and behaviors within a 24-hour cycle – Regulate all vital life functions Suprachiasmatic nucleus – – – – Structure in the hypothalamus The body’s biological clock Controls the timing of circadian rhythms Signals the pineal gland to secrete or suppress melatonin How do disruptions in circadian rhythms affect the body and the mind? Jet lag and working during subjective night disrupt circadian rhythms – Can lead to sleep difficulty and reduced alertness Subjective night – The time during a 24-hour period when the biological clock tells a person to go to sleep Sleep Before the 1950s, there was little understanding of what goes on during the state of consciousness known as sleep. From analyses of sleep recordings, known as polysomnograms, set up in sleep laboratories, researchers discovered two major types of sleep. What is the difference between the restorative and circadian theories of sleep? Restorative theory of sleep – The function of sleep is to restore body and mind Circadian theory of sleep – Sleep evolved to keep humans out of harm’s way during the night – Also known as the evolutionary theory How do NREM and REM sleep differ? NREM sleep – Non-rapid eye movement sleep – Characterized by slow respiration and heart rate, little body movement, and low blood pressure and brain activity REM sleep – Characterized by rapid eye movements, paralysis of large muscles, fast and irregular heart and respiration rates, increased brain activity, and vivid dreams – REM sleep may be critical to the consolidation of new memories after learning Sleep cycles During a typical night’s sleep, a person goes through about five 90-minute cycles What is the progression of NREM stages and REM sleep in a typical night of sleep? Stage 1 – Transition stage between waking and sleeping – Irregular EEG waves; some alpha waves Stage 2 – Deeper sleep than in stage 1 – Sleep spindles appear in EEG Stage 3 – Beginning of slow-wave sleep – EEG registers 20% delta waves Stage 4 – Deepest stage of NREM sleep – More than 50% delta waves How does age influence sleep patterns? Infants and young children – Sleep the longest – Have largest percentage of REM and slow wave sleep Children from 6 to puberty – Sleep best – Most consistent sleepers and wakers Adolescents – Sleep patterns influenced by schedules – Insufficient sleep may contribute to poor school performance Older adults – More difficulty falling asleep; sleep more lightly – Spend more time in bed, but less time asleep Average hours of sleep across the lifespan How does sleep deprivation affect behavior and neurological functioning? Effects of sleep deprivation – Difficulty concentrating – Impaired learning – Negative mood Effects on the brain – Decreased activity in temporal lobes during verbal learning tasks – Increased activity in prefrontal cortex and parietal lobes To compensate for decreased temporal lobe activity What are the various disorders that can trouble sleepers? Parasomnias is a sleep disturbance in which behaviors and physiological states that normally occur only in the waking state take place during sleep – Somnambulism (sleepwalking) Occurs during partial arousal from stage 4 sleep – Somniloquy (sleeptalking) Can occur in any stage – Sleep terrors Sleeper awakes in panicked state Happens during stage 4 sleep – Nightmares Frightening dreams during REM sleep What are the various disorders that can trouble sleepers? Dyssomnia is a category of sleep disorder in which the timing, quantity, or quality of sleep is impaired – Narcolepsy Disorder characterized by excessive daytime sleepiness and attacks of REM sleep – Sleep apnea Disorder in which breathing stops during sleep – Insomnia Difficulty falling or staying asleep, or waking too early Sleep that is light, restless, or of poor quality Dreams We generally think of dreaming as a pleasant, imaginative experience, but occasionally a frightening dream occurs. Good or bad, just what exactly is a dream? What have researchers learned about dreams, their biological basis, and their controllability? REM dreams – Have a storylike quality – More visual, vivid, and emotional than NREM dreams NREM dreams – Occur during NREM sleep – Less frequent and memorable than REM dreams Lucid dreaming – Set of techniques that enable dreamers to control the content of dreams How do the views of contemporary psychologists concerning the nature of dreams differ from those of Freud? Dreams satisfy unconscious sexual and aggressive desires These wishes are unacceptable to the dreamer and must be disguised in symbolic forms – Manifest content The content of a dream as recalled by the dreamer – Latent content The underlying meaning of a dream How do the views of contemporary psychologists concerning the nature of dreams differ from those of Freud? Activation-synthesis theory of dreaming – Dreams are the brain’s attempt to make sense of random firing of brain cells during REM sleep Evolutionary theory of dreaming – Vivid REM dreams enable people to rehearse skills needed to deal with threatening events Meditation and Hypnosis Other forms of altered consciousness that we may experience only if we choose to do so What are the benefits of meditation? Techniques used to block out distractions and achieve an altered state of consciousness by focusing attention on an object, word, one’s breathing, or body movements Can be helpful for a variety of physical and psychological problems – Controlling emotions – Lowering blood pressure What are the effects of hypnosis and how do theorists explain them? Procedure through which a hypnotist uses power of suggestion to change thoughts, feelings, sensations, perceptions, or behavior in the subject Has been used successfully to control pain What are the effects of hypnosis and how do theorists explain them? Sociocognitive theory – Behavior of a hypnotized person depends on that person’s expectations about how subjects behave under hypnosis Neodissociation theory – Hypnosis induces a dissociation between two aspects of the control of consciousness Planning function Monitoring function Theory of dissociated control – Hypnosis weakens control of the executive function over other parts of consciousness Psychoactive Drugs Any substance that alters mood, perception, or thought – Controlled substances are approved for medical use – Illicit substances are illegal How do drugs affect the brain’s neurotransmitter system? Psychoactive drugs create a sense of pleasure by increasing availability of dopamine in the nucleus accumbens, a part of the brain’s limbic system How drugs affect neurotransmission – Opiates mimic the effects of endorphins – Depressants act on GABA receptors – Stimulants mimic the effects of epinephrine What is the difference between physical and psychological drug dependence? Substance abuse – Continued use of a substance after several episodes in which use has negatively affected an individual's work, education, and social relationships Physical drug dependence – Compulsive pattern of drug use in which the user develops drug tolerance coupled with unpleasant withdrawal symptoms when the drug use is discontinued Psychological drug dependence – A craving or irresistible urge for the drug’s pleasurable effects How do stimulants affect behavior? Speed up activity in the central nervous system – Suppress appetite – Make people feel more awake, alert, and energetic Stimulants include – – – – Caffeine Nicotine Amphetamines Cocaine What are the behavioral effects of depressants? Decrease activity in the central nervous system – Slow down bodily functions – Reduce sensitivity to outside stimulation Sedative-hypnotics – Alcohol – Barbiturates – Minor tranquilizers (benzodiazepines) Narcotics (opiates) – Morphine, heroin – Oxycontin, Vicodin In what way do hallucinogens influence behavior? Drugs that can alter and distort perceptions of time and space, alter mood, cause hallucinations – Also called psychedelics Hallucinogens include – Marijuana – LSD – Designer drugs (e.g., MDMA or Ecstasy)